Lens gauge



N. M. BAKER LENSGAUGE V Filed April 21. 1926 nelson m. Baker.

v I u mmm;

Patented Feb. 21, 1928.

UNITED STATES PATE-NT. oFFIcE.

NELSON M. BAKER, OF SOUTHBRIDGE, MASSACHUSETTS, vASSIGNOR T AMERICANOPTICAL COMPANY, 0F SOUTHBRIDGE, MASSACHUSETTS, A VOLUNTARY vASSOCIA-TION OF MASSACHUSETTS.

LENS GAUGE.

Application iea'aprn 21, 192s. serial no. 103,626.

rIhis invention relates to plunger dial gauges and has particularreference tomeans for preventing grit and dirt getting into the gaugearound the plunger.

The object of this invention is to provlde improved means to preventdirt and grit entering the gauge around the orilice through which theplunger passes.

Other objects and advantages ol the invention will become apparent tromthe tollo1ving description taken in connection with the accompanyingdrawings, andit .will be apparent that many changes and modificationsmay be made in the details ot construction and arrangement ot' partswithout departing from the spirit of the invention within the scope ofthe appended claim. The preferred form only of the invention has beenshown by way of illustration.

Referring to the drawings in which similar characters ot' reference areused to denote corresponding parts throughout:

Figure l is a top or plan view partially in section;

l showing the location of the plunger.

In many forms of dial gauges the dial hand l is operated by areciprocating plunger or pin 2 passing through an orilice .in the wallsof the dial case 3. In addition to the plunger 2 there are twostationary or fixed pins Ll. The plunger 2 reciprocates back and Figure2 is an end or side view of `FigureA `extendingsome distance beyond thedial case. I also provide a contact head 6 for the plunger2 having aboss 7 which is recessed at 8 to lit over the sleeve 5. It will,therefore, be seen that the boss 7'itting over the sleeve 5 will preventthe dirt from coming in contact with the plunger 2 and evenfitl someforeign matter should get into the opening 8 it would be prevented fromgetting into the casing Y3 by the sleeve 5.

In operation it will be seen that as the plunger 2 is reciprocated theboss 7 can reciprocate back and forth over the sleeve 5, the oriliceSbeing long enough to allow for the total reciprocation of the plunger 2.

From the foregoing description it will be seen that I have providedsimple, inexpensive and ellicient means tor carrying out all the objectsof the invention.

Having described my invention, I claim:

In a gauge for measuring variations in distance from the center of thegauge to various pointsof a measured surface, a casing, a rotatableindicator, a reciprocal plunger in the casing and extending therebeyond,a sleeve bearing in the casing surrounding the plunger and wherein theplunger may reciprocate and extending beyond the casing, a pair ofseparated stationary contact points on the casing and extendingthereheyond one on each side of the plunger, said plunger having acontact point intermediate the stationary contact points7 and an annularsleeve bearing surrounding the lirst sleeve hearing adapted toreciprocate thereon asthe plunger is reciprocated, said annular sleevebeing in engagementrwith the first sleeve tor all positions of theplunger during its reciprocation.v 1

` NELSON M. BAKER.

